Here are the plugs that are removed from the bottom of the diffuser. I used the tool (gently) in the picture. There are 5 in total.
This is the bottom of the diffuser where the plugs go.
The side tabs are pictured below. Pull the diffuser away from the bumper at the tailpipe and work your way up. You need to push with your thumb where the tab meets the bumper and pull away with your other hand in the opening for the tailpipe.
The top tabs. When reinstalling, forcefully push from the outside where these are with your thumb or palm to align to the bumper.
